Digital biro art: James Mylne recreates three artworks from the National Portrait Gallery on a Surface Pro 3 tablet

Artist James Mylne has created three striking digital artworks based on paintings of well-known writers from London's National Portrait Gallery. James is best known for his can't-believe-their-hand-drawn portraits created using the humble biro, but for this project he was commissioned by Microsoft for the UK launch of its Surface Pro tablet - and he used that device to produce drawings of William Shakespeare, the Bronte sisters and Christabel Pankhurst.